Automatic veneer cutting apparatus



2 Sheets-Sheet l Nov. 11, 1969 TADASHI AIZAWA AUTOMATIC VENEER CUTTING APPARATUS Filed April 15. 19s? FIG.

FIG. 2

INVENTOR. A 2,4 WA

ATTORNEY N 1969 TADASHI AIZAWA AUTOMATIC VENEER CUTTING APPARATUS Filed April 13. 196? 2 Sheets-Sheet 2 FIG. 3

FIGQV4 fiDAS/l/ 4 /2522 ATTORNEY United States Patent 3,477,327 AUTOMATIC VENEER CUTTING APPARATUS Tadashi Aizawa, 24 S-chome, Dataku Shinmachi, Minamiku, Nagoya-ski, Aichi-ken, Japan Filed Apr. 13, 1967, Ser. No. 630,700 Int. Cl. B26d 5/38 U.S. Cl. 83-371 2 Claims ABSTRACT OF THE DISCLOSURE An apparatus is used to automatically cut a straight cut across pieces of wood veneer. The veneer pieces are carried by belts to below a cutting knife. A plurality of aligned electronic devices detect the front portion of the leading edge of each of the veneer pieces. The photo-electric device can also detect the rear edge of the veneer to cut off the back edge to form a straight edge. The photoelectric devices control operation of the knife by means of a time-delay circuit.

The present invention relates to apparatus for the cutting of wood veneer and more particularly to the automatic control of a cutting knife.

Veneer is a thin layer of wood. When the veneer is sliced from irregularly shaped pieces, the resulting pieces of vene'er have irregular edges. The veneer pieces, at that stage in their manufacture, have irregular back and front edges. To form a sheet of veneer, used, for example, on furniture, the edges of each of the pieces must be cut off evenly and joined toegther. The veneer sheet is formed from butt-joined pieces of veneer.

The cutting of the veneer pieces should be done so that the edge is even and without indentations. The cutting should be done so as not to Waste veneer, that is, the maximum available width of each piece should be utilized.

In a prior method of cutting the front and back edge of a veneer piece, an operator would judge, by eye, the position of the piece of veneer on the conveyor belt. The operator would, by a switch, stop the belt and bring down a cutting knife. This method was slow, expensive, and depended on the skill of the operator.

It is the objective of this invention to provide an apparatus for detecting the irregular shaped portions at both ends of a veneer piece, and to cut and transfer the piece automatically, even if the first and last edge of the narrow strips of veneer are of irregular and complex shapes.

It is another objective of this invention to provide an apparatus for automatically cutting and transferring a cracked portion of a veneer piece, after detecting of the maximum useable portion of the pieces.

In accordance with the present invention, a plurality of detecting devices are mounted on a transferring conveyor across the direction of movement of the veneer pieces. It is possible to use in this invention photo-diodes, limit switches, or non-contacting switches as the detecting devices. It is preferred to mount the plurality of detecting devices close together to detect the forms or shapes of the rearmost portion of the front edge and the foremost portion of the back edge of the narrow strips of veneer.

The conveyor belt carries the veneer pieces under the photo-electric detecting devices. Each of the detecting devices has a first contact, with each of the first contacts being connected in series with the other first contacts. All of the detecting devices must be activated, i.e., the last (rear) part of the front edge of the veneer Piece detected, before the knife is operated. The group of photo-electric detecting device contacts connected in series (first contacts) is connected in series with a time-delay relay device which controls the knife. Preferably, each of the detecting devices also has a second contact, or a second contact is arranged to operate oppositely to the first contact. The second contacts are open when the first contacts (those wired 1n series) are closed, and vice versa. The second conatcts are wired in parallel with each other. The second contacts are also connected in series with the time-delay relay. If any one of the second contacts is closed, then current flows to the time-delay circuit. The relay is spring, or otherwise, biased so that it is normally on, i.e., its contacts are closed except when the relay coil is supplied with current. But the relay coil is supplied with such current except for short interruptions. The photo-electric detecting devices, by operation of their switch contacts, permit a fiow of current to the relay, to keep its contacts open, except when the detecting devices change their state from being on to off, or off to on. When the detecting devices change state, the delay circuit causes a current interruption to the relay coil. The photo-detecting devices are on when they see light, i.e., when the veneer is not over the device. The time-delay circuit causes the state of the photo-detecting devices to produce a short interruption of current (short period of lack of current) to the relay coil. These interruptions permit the normally on relay to close its contacts, operate the knife and simultaneously stop the conveyor belt. The change in state of the photo-devices occurs on the rear-most portion of the front edge (light to dark) and frontmost portion of the back edge (dark to light) of the veneer piece. Preferably the final switch of the circuit controls the knife by means of a magnetic clutch which operates an air-pressure ram having the knife at its end.

In the preferred device a single circuit is used for cutting the front edge and rear edge of each veneer piece. The use of such a single circuit to perform both functions reduces the cost and the maintenance of the machine.

Other objectives of the present invention will be apparent from the following detailed description of a preferred embodiment taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a side view of the machine of the present invention;

FIG. 2 is a top plan view of the machine of FIG. 1;

FIG. 3 is a vertical sectional view taken along line III-III of FIG. 1 in the direction of the arrows; and

FIG. 4 is a diagram of the electrical circuit of the present invention.

The machine of the present invention consists of various parts connected together on a common base. The conveyor belt system 1 consists of four belts mounted in parallel on a transferring side conveyor frame 14. The narrow strips of veneer 3 are transferred in the direction of the arrow by means of the said conveyor belt system 1. The four belts run at the same speed. Preferably on both sides of the conveyor mechanism there are mounted vertical standing holding devices to prevent sidewise movements of the narrow strips of veneer and/or a device for holding the narrow strips of veneer when they are being cut. The second conveyor belt frame 14, in the transferring direction, is joined to the conveyor belt frame 14 through the side frames 12 and 12'. Four small area belt conveyors 7 are rotatably mounted on the said frame in parallel. The velocity of the conveyor belts 7 may be of an equal or a quicker speed than the belts 1. The belts 7 are driven by the same motor operating means (not shown) as the belts 1 or another operating motor means.

Frame 13 and fixed blade 11 are fixed between the side frames 12 and 12. An operating device 6 for the moving blade of the cutting knife 5 is fixed within the frame 13. This operating device 6 is connected electrically with timing devices 4 and 4'. The operating device preferably is an air-pressure-driven ram which is released by electrical switching of a magnetic clutch. Mounting means 2 is mounted over the conveyor belt 1 at the right angle to the transferring direction of the conveyor device and prior (in the conveying direction) to the cutting knife 5. A plurality of light sources photo-lamps 8, for example, bulbs, are fixed on the said mounting means 2 for transmitting light. Below the respective photo-lamps 8 there is mounted a plurality of photoelectric detecting devices 9. The photo-electric devices 9 receive a radiant of collected light from photo-lamps 8.

As shown in FIG. 4, the circuit includes a plurality of photo-responsive devices 9. Each such photo-responsive device 9 includes a first contact which is ON in circuit normally and a second contact 10' which is OFF in circuit normally. The showing in FIG. 4 is during operation when contacts 10 are open and contacts 10' closed, such operation being described below. With reference to the said contacts 10, when the light from the light source 8 which is picked up by the photo-responsive device 9 is interrupted, the contacts 10 will close and the contacts 10 will open. Preferably the photo-responsive device 9 includes a photo-diode which operates the contacts.

The contacts 10 and 10' are each connected together by a rod or other device, shown by the dashed lines between contacts 10 and 10'. When contacts 16 are opened, contacts 10' are closedand vice versa. Only one photoresp'onsive device 9 need open only one contact 10 to open its circuit, because the contacts 10 are wired in series. The timing devices 4 and 4, which are included in a controlling box 15, are connected electrically with the respective contacts 10 and 10'. In the controlling circuit of FIG. 4, the said contacts 10 are in the power source side of power transformer 16 and connected in series with a magnetic coil 17 in the said timing device 4. The said contacts 10' are wired to be connected with the power source side of power transformer 16 and will be contacted in parallel with the magnetic coil 17. The contacts 10 form an and circuit, all of whose contacts must close to provide current to coil 17. The contacts 10, in parallel, form an or circuit which will provide current to coil 17 if any of the contacts 10' are closed. From the above construction, these magnetic coils 17, 17 are the prepared means for driving the timed mechanism comprising the air-driven knife. In the said timing devices 4 and 4 there are prepared contacts 18 and 18, opened circuit normally, which will operate after a certain time when there is a flow of an electric current into magnetic coils 17 and 17', respectively. With regard to the operating device 6, this device consists of a timing device 19 and a magnetic coil 22. The driving of cutting knife 5 will be started and stopped by the said timing device 19. Operation for cutting and movement for driving a cutting knife 5 toward fixed blade 11 are done by an operating mechanism, for example, an electromagnetic clutch which controls the release of the blade. The electromagnetic clutch and air cylinder are controlled by the magnetic coil 22.

In the foregoing device 19, the magnetic coil 20 controls the closing of contacts point 21. It is OFF (closed circuit) normally and operates after a given time fixed by a delay circuit (not shown). Coil 20 is connected in parallel with contacts 18 and 18'.

The contacts 21 are joined in series with magnetic coil 22 and are connected with both sides of said magnetic coil 20. The switch contacts 21 will be operated when a narrow strip of veneer is not transferred, i.e., stopped because electric current through a contact point 10' of OFF-circuit normally to magnetic coil 17 flows; consequently, contact point 18 will be ON-circuit. And then magnetic coil 22 is excited by the electric current which passes through the contacts 21. As a result of the above operation, the prepared cutting knife 5 will be driven immediately when switching.

On the other hand, after the expiration of the given time fixed by the delay circuit, the contacts 21 will be OFF-circuit because a current flows also into magnetic coil 20. Subsequently, after a cutting knife 5 is driven one time only, the said knife 5 is reverted for the next driven movement. Thus, the situation of OFFcircuit for contacts 21 will be continued during the time current flows in coil 20.

When the ray of light from the light source lamp 8 is interrupted by the last part of the front edge of a narrow strip of the veneer 3, all the contacts 10 of photo-responsive devices 9 (which is an opened circuit ordinarily) will be closed, i.e., ON-circuit. Also, all the contacts 10 (of closed-circuit ordinarily) are opened. By the foregoing operation, immediately when detecting the rearmost portion of the leading edge of narrow strips of veneer, a contact 21 forms an ON-circuit since a current which flows to the magnetic coil 17 is interrupted. Subsequently, a closed circuit including a magnetic coil 17 will be formed. Thus, the momentary forming of an ON circuit, because of the time-delay circuit, permits the closing of contacts 21. Current will flow into the magnetic coil 22 through the contact point 21 due to forming an ON-circuit in the contact point 18 (opened circuit normally). The current path through contacts 21 is closed but coil 20 is not activated during the pause, i.e., delay period, of the time-delay circuit. The cutting knife 5 is driven one time only, and then a portion of the first edge of the narrow strips of veneer will be cut out. Since an electric current passes through the said magnetic coil 20 after the given delay period is over, the contact point 21 is opened.

When any one of the mounted light source lamps 8 shines through the veneer as a result of the appearance of cracking part of a last edge of narrow strips of veneer, one of the group of contacts 10 will return to its initial open condition, and the electric current which was being flowed is suddenly withdrawn from the magnetic coil 17. As a result, contacts 21 will be returned to ON- circuit at the same time the current is fed into the magnetic coil 17. But the current would be interrupted and. due to the delay circuit, the cutting knife 5 is driven and a portion of cracking or the last edge portion of narrow strip of veneer will be cut out. In this inven tion, such operation will be repeated to cut out the narrow strip veneer. In addition to the above, driving of conveyor belt 1 and 7 is started and stopped cooperatively with movement of magnetic coil 22.

While I have shown only the preferred forms of my invention, it should be understood that various changes or modifications may be made within the scope of the appended claims without departing from the spirit of the invention. With reference to the carried-out apparatus,

it is possible to combine a power transmitting signal.

The signal is timed to start a fixed. time after the blade 5 cuts off the front edge of the veneer piece. This signal insures that all pieces are equal in width, provided the pieces are at least as wide as the width provided for by the signal. This signal, which provides for a maximum width, may be adjusted to be proportional to the rate of movement of the conveyor belt.

I claim:

1. In an apparatus for the cutting of veneer pieces, a base table, conveyor means on said base to progress the veneer pieces, a cutting knife fixed to said base and movable to cut the veneer pieces, motor means to operate said knife, and control means to control the operation of said motor means, said control means including a plurality of light sources positioned proximate to said conveyor means and aligned perpendicularly to the direction of movement of said conveyor means, a plurality of photo-electronic responsive means associated with said light sources and positioned on the opposite side of said veneer pieces from said light sources, a plurality of normally open contacts connected in series and operated by said photo-responsive means, and a timedelay circuit connected in series with said contacts whose output controls the said motor means, wherein the photoresponsive devices are sensitive to the back edges of the veneer pieces and the control circuit includes a plurality of normally open contacts connected in parallel to said time-delay circuit, each of such normally open contacts being adapted to operate in the reverse state from said normally open contacts.

2. In an apparatus for the cutting of veneer pieces, a base table, conveyor means on said base to progress the veneer pieces, a cutting knife fixed to said base and movable to cut the veneer pieces, motor means to operate said knife, and control means to control the operation of said motor means, said control means including a plurality of light sources positioned proximateto said conveyor means and aligned perpendicularly to the direction of movement of said conveyor means, a plurality of photo-electronic responsive means associated with said light sources and positioned on the opposite side of said veneer pieces from said light sources, a plurality of normally open contacts connected in series and operated by said photo-responsive means, and a time-delay circuit connected in series with said contacts whose output controls the said motor means, wherein the photo-responsive devices are sensitive to the back edges of the veneer pieces and the control circuit includes a plurality of normally open contacts connected in parallel to said timedelay circuit, each of such normally open contacts being adapted to operate in the reverse state from said normally open contact, each of the said normally open contacts being connected to a normally closed contact.

References Cited UNITED STATES PATENTS 1,959,851 4/1933 Biggert 83-289 2,939,354 6/1960 King 83-371 X 3,011,375 12/1961 Muller 83364 X FRANCIS S. HUSAR, Primary Examiner Z. R. BILINSKY, Assistant Examiner U.S. Cl. X.R. 83--289, 364 

